Favorite Harems(different) and some ecchi:
1. Sumomomo Momomo (most outrageous, first line in the song is let's make babies...lol)
2. School Rumble
3. Zero No Tsukaima (half romantic, half harem)
Others that are meh...: Clannad series, Ouran High Host Club(it's just a comedy, you'll find more romance in shounen), Fruits Basket, Chobits(purely robot ecchi),
Other harem: As for School Days, it's not comedy, it's not romantic, it's just harem. I'd rather gouge my eyes out than watch that show again.